This invention relates to improved fletching assemblies that can be used on a variety of the state-of-the-art darts, and especially when used in combination with my copending application on a "composite Dart Body," Ser. No. 687,168, filed May 17, 1976, and my copending application, "Composite Filled Dart Body," Ser. No. 724,977, filed Sept. 20, 1976, provides superior darts of substantial improved construction and performance.
State-of-the-art darts are produced in a wide range of shapes, weights and designs, and they are constructed from a wide variety of materials, both metallic and non-metallic. Easily machined materials such as copper-base alloys, particularly various grades of brass, are commonly used for the dart bodies to provide a relatively low cost construction, free machining characteristics, adequate resistance to corrosion from the atmosphere and from human contact, and esthetic appearance. Higher density materials such as sintered tungsten-copper alloys are used in dart bodies of more advanced state-of-the-art darts. These state-of-the-art darts, as well as those of my copending applications cited, include a hardened metal point at the front which engages the target, but is not a feature of this invention except in combination with the improvements stated.
The fletching assembly at the rear of a dart is normally threaded into the dart body but may be joined by brazing as in my copending application, Ser. No. 687,168. Several prior art patents incorporate at least one metal pin which protrudes from the rear end of the fletching adaptor for mounting at least three bodies of folded sheet plastic material or other dart flight material. The pins are generally arranged parallel to each other, with each pin positioned in tangential contact with adjacent pins over part of their length. In some such designs, the ends of the pins are folded to prevent the blades from rotating with respect to the pins. In some other art, the pin may be in the form of a "U" shaped bent pin to secure the dart flights. These state-of-the-art designs are detrimental in that they stop or deflect subsequent darts that may be thrown in contact with the fletching assembly of a previously thrown dart. They also increase the chance of tearing the dart flights. The pins, especially when constructed of high carbon steel, can break under these conditions. An example of a multiple pin fletching adaptor is found in the following patents:
U.s. pat. No. 3,990,705 -- Nov. 9, 1976 Clarke (U.S.A.) PA1 U.s. pat. No. 3,995,861 -- Dec. 7, 1976 Clarke (U.S.A.) PA1 U.s. pat. No. 589,629 -- Feb. 13, 1945 Sulman (British) PA1 (1) Pins that spread open to allow contact of the pins at two positions on the dart flights, i.e., where the rounded heads contact the flights, and further forward where the shanks of the pins converge against the flights. PA1 (2) The convergence of the shanks of the pins is provided by seating their lead end against a stop in a recess in the aft end of a dart fletching assembly body, and further by circumferential compression provided by a heat shrinkable tube that overlaps the aft portion of the dart fletching assembly body and the rearwardly extending portion of the shanks of the pins up to the position where they abut the forward tips of the dart flights. PA1 (3) These features in combination hold the dart flights more securely and uniformly, permits precise and stable placement of the dart flights, reduces pin breakage, prevents wobbling of the flights in the thrown darts, and improves their balance, thus substantially increasing their thrown accuracy and uniformity from dart-to-dart. PA1 (4) These combined features minimize the tendency for the flights to tear or wear when they are inserted between the rounded head pins. PA1 (5) The heat shrinkable tubing is fitted over a reduced diameter with a detent (undercut) in the OD of the aft of the dart fletching assembly body, which feature reduces the strain and breakage of the pins for nearly their entire length. PA1 (6) The heat shrinkable tubing also tends to prevent penetration of subsequently thrown darts into the fletching assembly body. PA1 (7) The improved fletching assembly of this invention is constructed of low density materials to reduce its weight to a minimum. The fletching assembly body can also be of minimum length, and be partially hollow, if desired, to further reduce its weight. PA1 (8) Various length fletching assemblies to suit player's preferences, while keeping the total assembly weight to a minimum, is achieved by keeping the fletching assembly body to a minimum length and by using a hollow interior, while using rounded head pins and heat shrinkable tubing of desired lengths to achieve the desired overall length of the entire fletching assembly. PA1 (9) The threads or other means for attachment of the fletching assembly to the dart body can be sealed with a "Nyloc" type of plastic applied to the threads; or the threads can be dipped in a thermosetting plastic or other suitable potting compound to lock then in place. This feature provides a firm seating of the fletching assembly to the dart body, preventing them from unscrewing, and making them act as an integral unit dart. PA1 (10) All of the above improvements in combination improve and minimize deflection characteristics of subsequently thrown darts that impinge on previously thrown darts, and provide rugged and accurate darts of superior uniformity and scoring capabilities.
Furthermore, these state-of-the-art dart pin-type fletching assemblies hold the dart flights at only one point where the pins pinch against the flights; thus, they do not provide positive and secure location of the dart flights; also, the length of the pins often vary in the assembly which adversely affects their balance.